1. Field of the Invention
The present invention relates to a destination address area detection apparatus for detecting a destination address area where a destination of postal piece is written.
2. Description of the Related Art
Conventionally, in such a destination address area detection apparatus, a postal piece image is divided into several parts to obtain some parts containing a part of a destination. (Hereinafter, an area of destination address will be referred to as a destination address area, and the partial areas of a postal piece image will be referred to as destination address area candidates.) In this case, it is necessary to output a destination address area without detecting an addresser area having identical configuration as the destination address.
To cope with this, a destination likelihood degree is assigned to each of the destination address area candidates and only a predetermined number of candidates are output. For example, proceedings of 13th International Conference on Pattern Recognition, Volume III Track C contains Adrian P. Whichello and Hong Yan xe2x80x9cLocating Address Blocks and Postcodes in Mail-Piece Images (PP. 716 to 720), which (page 719) describes a method to select an address area candidate, starting at a location immediately below the center line of a postal piece image, utilizing that the smaller the distance from the center line, the address area candidate has a higher probability to be an address area.
However, this conventional method has a problem that an addresser area having an identical configuration as the destination address may be recognized as a destination address.
It is therefore an object of the present invention to provide an address area detection apparatus capable of reducing the danger of erroneous detection of an addresser address as a destination address and enhancing the address area detection accuracy.
The destination area detection apparatus according to the present invention comprises: destination area candidate generator for generating a plurality of destination area candidates including a destination area according to partial images of a mail piece image; feature amount calculator for calculating a feature amount of each of the destination area candidates; storage unit for storing in advance a feature amount and a destination probability representing probability that a destination area candidate is a destination area according to the feature amount, in correlation with an addresser probability which is a probability of an area having an address configuration other than the destination; feature amount converter for converting the feature amount of each of the destination area candidates into a destination probability and an addresser probability while referencing the storage unit; sorting unit for deciding the order of the destination area candidates in a descending order of the destination probability according to the destination probability and the addresser probability; and destination area selector for selecting a predetermined number of destination area candidates having higher destination probabilities.
This invention takes into consideration not only the probability that a destination area candidate created according to a partial image of a mail piece image is a destination, but also an addresser probability of a destination area candidate other than a destination area but having an address configuration. By using the destination probability and the addresser probability, the order of the destination area candidates is determined, and a predetermined destination area candidate are selected according to the order obtained. This reduces an erroneous detection of an area other than a destination but having an address configuration, thus increasing the detection accuracy of the destination area.